The Great Wall of China is a series of fortifications made of stone, brick, tamped earth, wood, and other materials, generally built along an east-to-west line across the historical northern borders of China in part to protect the Chinese Empire or its prototypical states against intrusions by various nomadic groups or military incursions by various warlike peoples or forces. Several walls were being built as early as the 7th century BC; these, later joined together and made bigger and stronger, are now collectively referred to as the Great Wall. Especially famous is the wall built between 220–206 BC by the first Emperor of China, Qin Shi Huang. Little of that wall remains. Since then, the Great Wall has on and off been rebuilt, maintained, and enhanced; the majority of the existing wall is from the Ming Dynasty.

Other purposes of the Great Wall have included border controls, allowing the imposition of duties on goods transported along the Silk Road, regulation or encouragement of trade and the control of immigration and emigration.

Furthermore, the defensive characteristics of the Great Wall were enhanced by the construction of watch towers, troop barracks, garrison stations, signaling capabilities through the means of smoke or fire, and the fact that the path of the Great Wall also served as a transportation corridor.

The collection of walls known today as the Great Wall of China was referred by a number of different names.

Early Arabs had heard about China's Great Wall during earlier periods of China's history as early as the 14th century. They associated it with Dhul-Qarnayn's Gog and Magog wall of the Qur'an, as the North African traveler Ibn Battuta heard from the local Muslim communities in Guangzhou around 1346.

Soon after Europeans reached the Ming China in the early 16th century, accounts of the Great Wall started to circulate in Europe, even though no European was to see it with his own eyes for another century.

When China opened its borders to foreign merchants and visitors after its defeat in the First and Second Opium Wars, the Great Wall became a main attraction for tourists. The travelogues of the later 19th century further enhanced the reputation and the mythology of the Great Wall, such that in the 20th century, a persistent misconception exists about the Great Wall of China being visible from the Moon or even Mars.

The sections of the Great Wall around Beijing municipality are especially famous: they were frequently renovated and are regularly visited by tourists today. The Badaling Great Wall

near Zhangjiakou is the most famous stretch of the Wall for this was the first section to be opened to the public in the People's Republic of China, as well as the showpiece stretch for foreign dignitaries. South of Badaling is the Juyong Pass , when used by the Chinese to protect their land, this section of the wall had many guards to defend China’s capital Beijing. Made of stone and bricks from the hills, this portion of the Great Wall is 7.8 meters (26 ft) high and 5 meters (16 ft) wide.

More than 60 km (37 mi) of the wall in Gansu province may disappear in the next 20 years, due to erosion from sandstorms. In places, the height of the wall has been reduced from more than 5 metres (16 feet) to less than 2 metres (6.6 ft). The square lookout towers that characterize the most famous images of the wall have disappeared completely. Many western sections of the wall are constructed from mud, rather than brick and stone, and thus are more susceptible to erosion. In August 2012, a 30-meter (98 ft) section of the wall in north China's Hebei province collapsed after days of continuous heavy rains.

One of the earliest known references to this myth appears in a letter written in 1754 by the English antiquary William Stukeley. Stukeley wrote that, "This mighty wall of four score miles in length (Hadrian's Wall) is only exceeded by the Chinese Wall, which makes a considerable figure upon the terrestrial globe, and may be discerned at the Moon."

آیا دیوار چین از کره ماه دیده می شود

The claim was also mentioned by Henry Norman in 1895 where he states "besides its age it enjoys the reputation of being the only work of human hands on the globe visible from the Moon." The issue of "canals" on Mars was prominent in the late 19th century and may have led to the belief that long, thin objects were visible from space. The claim that the Great Wall is visible also appears in 1932's Ripley's Believe It or Not! strip and in Richard Halliburton's 1938 book Second Book of Marvels.

The claim the Great Wall is visible has been debunked many times, but is still ingrained in popular culture. The wall is a maximum 9.1 m (30 ft) wide, and is about the same color as the soil surrounding it. Based on the optics of resolving power (distance versus the width of the iris: a few millimeters for the human eye, meters for large telescopes) only an object of reasonable contrast to its surroundings which is 70 mi (110 km) or more in diameter (1 arc-minute) would be visible to the unaided eye from the Moon, whose average distance from Earth is 384,393 km (238,851 mi). The apparent width of the Great Wall from the Moon is the same as that of a human hair viewed from 3.2 kilometres (2 mi) away. To see the wall from the Moon would require spatial resolution 17,000 times better than normal (20/20) vision. Unsurprisingly, no lunar astronaut has ever claimed to have seen the Great Wall from the Moon.

A satellite image of a section of the Great Wall in northern Shanxi, running diagonally from lower left to upper right (not to be confused with the much more prominent river running from upper left to lower right). The region pictured is 12 by 12 kilometres (7.5 mi × 7.5 mi). A more controversial question is whether the Wall is visible from low Earth orbit (an altitude of as little as 160 kilometres (100 mi)). NASA claims that it is barely visible, and only under nearly perfect conditions; it is no more conspicuous than many other man-made objects.

Astronaut William Pogue thought he had seen it from Skylab but discovered he was actually looking at the Grand Canal of China near Beijing. He spotted the Great Wall with binoculars, but said that "it wasn't visible to the unaided eye." U.S. Senator Jake Garn claimed to be able to see the Great Wall with the naked eye from a space shuttle orbit in the early 1980s, but his claim has been disputed by several U.S. astronauts. Veteran U.S. astronaut Gene Cernan has stated: "At Earth orbit of 100 to 200 miles (160 to 320 km) high, the Great Wall of China is, indeed, visible to the naked eye." Ed Lu, Expedition 7 Science Officer aboard the International Space Station, adds that, "it's less visible than a lot of other objects. And you have to know where to look."

In 2001, Neil Armstrong stated about the view from Apollo 11: "I do not believe that, at least with my eyes, there would be any man-made object that I could see. I have not yet found somebody who has told me they've seen the Wall of China from Earth orbit. ...I've asked various people, particularly Shuttle guys, that have been many orbits around China in the daytime, and the ones I've talked to didn't see it."

In October 2003, Chinese astronaut Yang Liwei stated that he had not been able to see the Great Wall of China. In response, the European Space Agency (ESA) issued a press release reporting that from an orbit between 160 and 320 kilometres (99 and 199 mi), the Great Wall is visible to the naked eye. In an attempt to further clarify things, the ESA published a picture of a part of the “Great Wall” photographed from low orbit. However, in a press release a week later (no longer available in the ESA’s website), they acknowledged that the "Great Wall" in the picture was actually a river.

Leroy Chiao, a Chinese-American astronaut, took a photograph from the International Space Station that shows the wall. It was so indistinct that the photographer was not certain he had actually captured it.

I tracked this wall with my close friend Dr. Sehatkhah ( دکتر صحت خواه ) on August 2014 from Badaling gate, in fact we tracked only 5 kilometers i.e. less than 1/1000 of great wall ( در واقع ما کمتر از 1/1000 مسیر دیوار چین را پیمودیم ) this means that if you can track 8 hours per day, you need at least 1 year to get this wall totally .

The way is very easy and short in 3 hours, but you need a lot of water and fruit for your one day program, you need more time to get badaling from beijing and coming back, try to go early morning even 6:00 am and be care about holidays, it will be so busy and hard traffic, sometime you have a long Que , maybe some kilometers for bus or train on holidays.(we had the same position)

Maybe it is better to prepare timetable of express train of badaling before. Try and enjoy as well as other attractions of Beijing like summer place, heaven temple, forbidden city and lama temple as well as tiananmen square to remember the tragedy of students protests last decade, I remember it happen when I was a young boy.

Beside all of long story of china, ( I think as long as the history of world ) Beijing as an attractive place isn't a city, it is a magnificent world . Trust me.

the highest tower tower north 8

path

coming back path

end of path

3 Kommentare

Near soon you will see gallery. The hotel was near Tienanmen square just in the center of Beijing. you can move the map and see beijing in south east of badaling it is 75 kilometers from great wall in south east . try to enlarge of map and see the smallest circle of beijing. this is the center of beijing city (beiging = pekan). the path from beijing to badalan can tried by express train in 1 hour or by bus in 3 hours. It is a path with 120 degree from beijing75 kilometers g110 and g6 from chaoyang near our hotel.

Its great to find a well described and llustrated track on Changcheng (the Great Wall) and am thrilled to realize you are posting from Iran. I wish I had Wikiloc when I worked as a geologist in Iran many years ago with Dr. Hassan Salehi.